Remove unneeded bash dependency

Hello guys,

I tried to compile
https://ftp.postgresql.org/pub/pgadmin3/release/v1.22.1/src/pgadmin3-1.22.1.tar.gz
on OpenBSD 5.8 and it failed because the shell script
pgadmin/ver_svn.sh shebang pointed to /bin/bash, which I don't have.
Looking into the script, it doesn't use any bash specific idiom. I
made a symbolic link /bin/bash pointing to /bin/sh and the build
process completed successfully. I grepped the rest of the source for
/bin/bash and the other places where bash is used are:

bootstrap
pkg/mac/create-dmg.sh
pkg/mac/debug-bundle.sh

I didn't try to use the bootstrap script because I didn't clone from a
git repository. The mac references I have no way to test because I
don't have a mac.

Thus, for the sake of portability, I suggest that the
pgadmin/ver_svn.sh file be modified to use /bin/sh instead, since it
uses only simple sh structures.

Thank you,
Daniel Camoles.